How do I map a class using spring data and r2dbc in kotlin

Question

The org.springframework.r2dbc DatabaseClient class has moved to

import org.springframework.r2dbc.core.DatabaseClient;

from

import org.springframework.data.r2dbc.core.DatabaseClient;

The Spring data documentation https://spring.io/projects/spring-data-r2dbc refers to a simple 'as' method to convert to an object

   databaseClient
        .sql("select * from reading")
        .as(CrepsReading::class.java)
        .fetch()
        .all()
        .asFlow()

It doesn't wok. Neither does map(class). Only mapping class seems to work.

     val all: Flux<CrepsReading> = databaseClient
            .sql("SELECT id, name FROM person")
            .map(CrepsReading::class)
            .fetch().all()

How do you map an object with spring-data-r2dbc (1.2.0) simply? Is there documentation that describes the use of the DatabaseClient that is part of spring-data-r2dbc?

Answer 1

In Spring 5.3/Spring Data R2dbc, the DatabaseClient is refactored and moved to the core of Spring framework.

Check my example to view how to handle the resulting map.

    public static final BiFunction<Row, RowMetadata, Post> MAPPING_FUNCTION = (row, rowMetaData) -> Post.builder()
            .id(row.get("id", UUID.class))
            .title(row.get("title", String.class))
            .content(row.get("content", String.class))
            .status(row.get("status", Post.Status.class))
            .metadata(row.get("metadata", Json.class))
            .createdAt(row.get("created_at", LocalDateTime.class))
            .build();

    private final DatabaseClient databaseClient;

    public Flux<Post> findByTitleContains(String name) {
        return this.databaseClient
                .sql("SELECT * FROM posts WHERE title LIKE :title")
                .bind("title", "%" + name + "%")
                .map(MAPPING_FUNCTION)
                .all();
    }